The Season’s Changing Stars

Winter’s constellations are on the way out, while spring’s are here to stay

By J. Alex Knoll

As the sun sets Thursday evening the waxing crescent moon appears high in the south, its lower tip pointing to the star Aldebaran a few degrees away. Aldebaran is a red-giant that marks the eye of Taurus the bull. Just to the left of the moon is the Hyades cluster, a V-shaped pattern of stars that make up the face of the bull. Higher above the moon is the Pleiades cluster, marking the bull’s shoulder. Named after the seven daughters of Atlas, six of the mythological sisters are visible to the naked eye. How many can you spot?
Saturday the moon shines near Jupiter, the next-brightest object in the night sky. The Gemini twins Castor and Pollux are above Jupiter, while below the moon is the bright orange star Betelgeuse, the shoulder of Orion. The next night the waxing moon is just a few degrees below Jupiter, well within the field of view of binoculars. Surrounding the moon and Jupiter are the bright stars of the Great Winter Circle (which looks more like a hexagon): Aldebaran, Rigel, Sirius, Procyon, Pollux, Castor and Capella. Within the circle is Orion’s bright-red star Betlegeuse. This is the last month to catch these winter luminaries as they shift to the west and out of sight.
While Jupiter fades with the stars of winter, Mars is at its prime amid the stars of spring. The red planet appears low in the east at sunset with the blue-white star Spica five or six degrees to its lower right. Mars reaches opposition on the 8th, at which point it rises as the sun sets and does not set until sunrise the next morning. This is its best apparition all year, and only Jupiter and Venus shine brighter.
Saturn rises in the southeast around 10:30pm, is at its highest in the south around 3am and is low against the southwest horizon at daybreak. The planet is tilted in such a way that its rings are on full display with even a small telescope. The ringed planet is in the middle of Libra and forms a tight triangle with the constellation’s two brightest stars. To the west of Saturn and marking the balance’s fulcrum is Zubenelgenubi, while above the planet and marking the upper scale is Zubeneschamali, which has the distinction of being the only star that glows with a green hue. Not everyone can distinguish the color; can you? Zubenelgenubi is Arabic for the southern claw, while Zubeneschamali translates to the northern claw, namesakes from when these stars were part of the constellation Scorpius. The last of the planets visible this week rises before dawn. There is no mistaking Venus above the southeast horizon shining at magnitude –4.5, exponentially brighter than even the brightest star. Venus doesn’t climb very high, but it will hold this position in the early morning through spring and summer.